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Texas Instruments LM2599SX-5.0
- Part No.:
- LM2599SX-5.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2599SX-5.0.pdf
- Description:
- IC REG BUCK 5V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,574
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Product details
Overview
LM2599SX-5.0 from Texas Instruments is a monolithic 150 kHz step-down (buck) switching voltage regulator IC delivering a fixed 5.0 V output at up to 3 A, with ±4% output voltage tolerance over line and load, input voltage range up to 40 V, and integrated thermal shutdown and current limiting - used in on-card DC/DC conversion for industrial power supplies and embedded systems.
For engineers reviewing the LM2599SX-5.0 datasheet, LM2599SX-5.0 pinout, LM2599SX-5.0 application, or LM2599SX-5.0 equivalent, key selection considerations include its fixed 5 V output, 7-pin TO-263 surface-mount package, 80 μA standby quiescent current, 150 kHz fixed-frequency oscillator, and compatibility with standard off-the-shelf inductors and Schottky catch diodes.
Technical Context
The LM2599SX-5.0 implements a current-mode PWM buck topology with internal 150 kHz oscillator, two-stage current limit protection, and built-in soft-start via external capacitor on the SS/SD pin. It uses an N-channel MOSFET switch with 1.16 V typical saturation voltage at 3 A, enabling high-efficiency operation without external gate drive circuitry.
Its feedback loop references a precision 1.23 V internal bandgap, but for fixed-output versions like LM2599SX-5.0, the error amplifier and resistive divider are fully internal - eliminating external resistor networks while maintaining ±4% output accuracy across −40°C to +125°C junction temperature and 7 V–40 V input range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±4% (ensured min/max: 4.80 V / 5.20 V at full temp & load) |
| Max Output Current | 3 A continuous (with thermal derating above 125°C junction) |
| Input Voltage Range | 7 V to 40 V (absolute max 45 V; enables 12 V/24 V rail regulation) |
| Switching Frequency | 150 kHz fixed (enables compact LC filter design with standard inductors) |
| Quiescent Current | 5 mA operating; 80 μA in shutdown (supports low-power standby modes) |
| Efficiency | 80% typical at VIN = 12 V, IOUT = 3 A (reduces thermal load vs linear regulators) |
| Thermal Resistance | θJA = 30°C/W (TO-263 with 2.5 in² copper); θJC = 2°C/W (direct heatsink path) |
Pinout & Package
LM2599SX-5.0 is housed in a 7-lead TO-263 (KTW) surface-mount package with exposed thermal pad. The package supports high-current PCB layout and direct heatsinking via the tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN | Input Power Supply | Accepts 7–40 V DC; requires local 470 μF low-ESR input capacitor |
| OUT | Regulated Output | Delivers fixed 5.0 V; connects to output inductor and feedback network (internal) |
| GND | Power Ground | Common return for input/output paths and internal control circuitry |
| FB | Feedback Input | Internally connected to 5 V divider; not accessible on fixed-output variants |
| SS/SD | Soft-Start / Shutdown | Pulled low (≤0.6 V) disables regulator; rising edge initiates 1–2 ms soft-start ramp |
| FLAG | Error Flag Output | Open-drain active-low signal asserting when output drops below 96% of nominal |
| DELAY | Flag Delay Control | External capacitor sets delay time before FLAG asserts during dropout |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Soft-Start | Programmable via external capacitor on SS/SD pin; prevents inrush current at startup |
| Out-of-Regulation Flag | Dedicated open-drain FLAG pin with adjustable delay (via DELAY capacitor) for system monitoring |
| Two-Stage Current Limit | Peak current limit (3.6–6.9 A) plus foldback protection prevents switch failure under overload |
| Thermal Shutdown | Activates at +150°C junction; auto-recovery after cooldown ensures robust fault handling |
| Standard Inductor Compatibility | Designed for widely available 33–68 μH through-hole and SMT inductors (e.g., L38, L40 series) |
Applications
| Industrial Power Supply | Embedded System Rail |
|---|---|
Use Scenario: Regulating unregulated 12 V or 24 V DC bus to stable 5 V for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Primary buck converter delivering 3 A continuous output with ±4% regulation under varying load and temperature. Use Value: Eliminates need for external feedback resistors and simplifies BOM with fixed 5 V output and integrated protection. | Use Scenario: Providing clean 5 V supply to microcontrollers, FPGAs, and communication peripherals on dense PCBs. IC Role / Device Role / Timing Role: On-card DC/DC converter with 150 kHz fixed frequency minimizing EMI and enabling predictable filter design. Use Value: TO-263 thermal pad allows direct heatsinking; 80 μA shutdown current extends battery-backed runtime. |
| Pre-Regulator for Linear LDO | Positive-to-Negative Converter |
Use Scenario: Stepping down 24 V industrial rail to ~6–7 V before feeding low-dropout linear regulator for ultra-low-noise analog rails. IC Role / Device Role / Timing Role: High-efficiency pre-regulator reducing power dissipation in downstream LDOs by >60% vs direct 24 V → 5 V linear conversion. Use Value: 80% efficiency at 3 A load minimizes heat generation, enabling smaller heatsinks and higher system power density. | Use Scenario: Generating −5 V from +5 V or +12 V supply using inverting buck-boost configuration (per Figure 24). IC Role / Device Role / Timing Role: Switching controller repurposed as inverting regulator via modified external component topology. Use Value: Leverages same 150 kHz oscillator and current-limit architecture - no additional IC required for dual-rail designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-5.0 | Same pinout, lower 1.5 A output rating, 150 kHz frequency, no FLAG/DELAY pins | Lacks error flag and programmable delay; suitable only for non-critical 5 V loads ≤1.5 A | Select LM2596SX-5.0 only if cost sensitivity outweighs need for 3 A output and fault monitoring. |
| MP1584EN-LF-Z | 4 A output, 1.5 MHz switching, SOIC-8 package, no integrated FLAG/DELAY | Higher frequency enables smaller magnetics but increases EMI filtering complexity; no native error flag | Choose MP1584EN-LF-Z when board space is constrained and 1.5 MHz operation is acceptable; add discrete monitoring if FLAG required. |
Compared with LM2596SX-5.0 and MP1584EN-LF-Z, the LM2599SX-5.0 uniquely combines 3 A capability, dedicated FLAG/DELAY monitoring, and TO-263 thermal performance - making it optimal for industrial applications requiring reliability, fault visibility, and thermal headroom without layout redesign.
Availability
LM2599SX-5.0 is available at Aetrix Electronics and suitable for industrial power supplies, embedded system rails, and pre-regulator circuits requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2599SX-5.0 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2599 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use, minimal external component count, and robust operation in industrial, automotive, and telecom power systems.
FAQ
What is the maximum input voltage rating for LM2599SX-5.0?
The absolute maximum input voltage for LM2599SX-5.0 is 45 V, but the recommended operating range is 7 V to 40 V per the datasheet. Exceeding 40 V may trigger overvoltage stress on internal components and reduce long-term reliability. For 40 V operation, ensure adequate thermal margin and use input capacitors rated ≥50 V.
Does LM2599SX-5.0 require external feedback resistors?
No - LM2599SX-5.0 is a fixed-output variant with internal feedback divider set for 5.0 V. The FB pin is not accessible externally and must remain unconnected. This eliminates resistor tolerance errors and simplifies layout versus adjustable versions like LM2599ADJ.
How does the FLAG pin function on LM2599SX-5.0?
The FLAG pin on LM2599SX-5.0 is an open-drain output that pulls low when regulated output falls below 96% of nominal (i.e., <4.8 V). Its assertion delay is controlled by an external capacitor on the DELAY pin, allowing configurable response time to transient faults without false triggering.
Can LM2599SX-5.0 be used in a negative-output configuration?
Yes - LM2599SX-5.0 can be configured as a positive-to-negative inverting buck-boost converter per Figure 24 in the datasheet. This requires repositioning the inductor and diode, grounding the OUT pin, and taking output from the IN node - retaining all internal regulation and protection features of LM2599SX-5.0.
What thermal management is required for LM2599SX-5.0 at 3 A output?
At 3 A and 12 V input, LM2599SX-5.0 dissipates ~2.1 W. With θJA = 30°C/W (TO-263 on 2.5 in² copper), junction rise is ~63°C above ambient. To maintain TJ ≤125°C, ambient must stay ≤62°C - achieved using the exposed thermal pad soldered to ≥2.5 in² of 1 oz. copper and optional small heatsink.
LM2599SX-5.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-7)
LM2599SX-5.0 FAQ
1.How can I place an order for LM2599SX-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2599SX-5.0 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM2599SX-5.0 reliable?
The price and inventory of LM2599SX-5.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2599SX-5.0 is usually 5 days.
3.What payment methods are accepted for LM2599SX-5.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2599SX-5.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2599SX-5.0?
LM2599SX-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2599SX-5.0 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM2599SX-5.0?
For technical support, including LM2599SX-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2599SX-5.0 requirements.
6.How does Aetrix verify that LM2599SX-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2599SX-5.0 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM2599SX-5.0 meets industry standards.
7.What is the process for return or replacement of LM2599SX-5.0?
All LM2599SX-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2599SX-5.0, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM2599SX-5.0 part is unused and in its original packaging.
Return procedure for LM2599SX-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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